1. Field of the Invention
The present invention relates to hydraulic couplings used in undersea drilling and production applications and junction plates used to support the opposing members of the coupling. More particularly, the invention involves a sliding lock plate for restraining axial movement of the male and female coupling members, which can be connected or disconnected simultaneously from one or more coupling members.
2. Description of the Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with sealed fluid passageways connecting therebetween. The female member generally is a cylindrical body with a relatively large diameter longitudinal bore at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore seals and slidingly engages the male member of the coupling.
Subsea hydraulic couplings are shown, for example, in U.S. Pat. Nos. 4,694,859 and 4,754,780 to Robert E. Smith, III, assigned to National Coupling Co., Inc. of Stafford, Tex.
The male member includes a cylindrical body having an outer diameter approximately equal to the diameter of the large female bore, and a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical body of the male member is inserted into the large bore of the female member, according to various embodiments of the device, fluid flow is established between the male and female members.
A male member and female member are generally connected to opposing junction plates of a manifold and are held together by bolts or hydraulic members attached to the plates. The male member is commonly attached to one junction or manifold plate, while the female member is attached to an opposing plate so as to face the male member and align with it. The male and female members may be attached to the junction or manifold plates using various means, such as set screws or threads. Techniques for attaching the members to such plates are well-known to those skilled in the art.
Typically, several subsea hydraulic connectors are grouped together on each junction or manifold plate. For example, between ten and thirty coupling members may be attached to each opposing plate. In the subsea environment, a diver is required to connect the opposing plates together, and thereby connect the opposing coupling members on the plates. The coupling members are simultaneously connected and the opposing plates are locked together.
High separational forces are transferred to the opposing junction plates, due to the separational forces of the high pressure fluid in each coupling member. In many cases, the plates must be relatively thick and heavy in order to withstand high separational forces. For example, the plates are typically stainless steel and between 1 - 1 1/2 inches in thickness.
The weight and thickness of the stainless steel plates present certain problems. To handle each heavy plate, several divers are required, and a wire line and/or cable and hoist also may be required to move and position the plate. Additionally, even with relatively heavy, thick manifold plates, it is impossible to completely eliminate relative axial or longitudinal movement between each of the coupling members. Warping of the plates may result in displacement of the male member with respect to the female member, resulting in loss of fluid communication between the coupling members. This displacement can be a serious problem, especially with subsea hydraulic couplings grouped together on opposing manifold plates.
Attempts have been made in the past to eliminate or reduce the problems due to high separational forces of the couplings and reduce the thickness and weight of the manifold plates. One solution that has been proposed is to individually lock together the male and female member in each of the hydraulic connectors, rather than locking only the plates together. In a subsea environment, however, individually connecting each of the hydraulic coupling members together can be an extremely difficult and time consuming undertaking.
Another proposed solution is lock sleeves for the subsea hydraulic connectors. The lock sleeves simultaneously lock together each of several couplings grouped together on opposing junction plates. The lock sleeve is pulled back axially to release balls inside the female half of the connector and thereby permit interconnection of the male half of the connector with the female member. After the male member has entered and seated in the female member, the lock sleeve is released, allowing the balls to reposition in the female and lock the male member and female member together. All of the lock sleeves are connected to a plate interposed between the male and female plates. As the intermediate plate is pulled back, all of the lock sleeves are simultaneously pulled back from the female coupling members. When the intermediate plate is released, the lock sleeve allows the balls to reposition in the female members and thereby lock each of the male members. The intermediate plate includes a handle that is used to move the intermediate plate axially to pull back and release each of the sleeves.
The lock sleeve system described above, however, has a number of disadvantages. The lock sleeve system is relatively heavy and bulky, which is undesirable in the subsea environment. Additionally, the lock sleeve system requires substantial vertical clearance sufficient to allow for the longitudinal movement of the intermediate plate. Other problems are caused by a build-up of silt, ocean debris and marine growth in the lock sleeve. The build-up may result in jamming the lock sleeves and especially the small locking balls. The connectors therefore cannot be released without great difficulty after a period of time subsea. Therefore, a reliable solution is needed for the problem of simultaneously locking together each subsea connector and that can easily be handled by a diver in the subsea environment.